The development of antigen specific therapy for multiple sclerosis (MS) involves specifically suppressing undesired immune responses targeting the myelin sheath and underlying axon. We have recently reported some success with altered peptide ligands for a major target of the autoimmune response in MS. Antigen specific therapy has the potential to suppress undesirable autoimmunity, while leaving the rest of the immune system intact. Induction of an antigen specific Th1-to-Th2 shift could achieve this aim, once side effects, such as allergic responses, are minimized with optimal dosing.